To configure spanning tree settings that will affect all ports, click Bridge Settings and configure the necessary settings.

NOTE: You can also disable Spanning Tree all together.

Click Apply at the bottom of the page to save the changes. (Figure 7)

Figure 7 - Bridge Settings

To configure spanning tree for a specific port, click Port Settings and make the necessary changes. Click Apply at the bottom of the page to save the changes. (Figure 8)

Figure 8- Port Settings

When done, click Save Configuration to save the changes to NVRAM.

More information on the Spanning Tree Protocol.

Spanning-Tree Protocol (STP) was developed to prevent multiple open paths to the same switch (loops). There is an algorithm called STA (Spanning-Tree Algorithm) that is used to calculate a loop-free network topology.

Each port sends small packets addressed to itself and if it receives one back, it knows that there is a loop somewhere in the configuration and the switch will set that port to blocking mode. This process disables it for normal network traffic (Spanning Tree packets will still be allowed to pass).

When the Spanning Tree protocol is enabled the following parameters can be configured:

Hello Time - The interval between configuration messages sent by the spanning tree algorithm.

Max Age - The amount of time before a configuration message is discarded by the system.

Forward Delay - The amount of time the system spends in "learning" and "listening" states.

Bridge Priority - The priority setting amongst other switches in the spanning tree.

In some cases, it may be necessary to set certain ports to Fastlink, which disables Spanning Tree for that port only (as disabling Spanning Tree for the entire switch is generally not desirable). This is typically done to resolve timeout issues with DHCP clients that boot especially fast. Spanning Tree has a 30 second timeout period in which the port will be set to blocking mode until the algorithm can ascertain if there are loops. When a DHCP client boots up while the port is still in blocking mode, it can prevent it from obtaining an IP address.

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